Document Type

Student Presentation

Presentation Date

4-21-2014

Faculty Sponsor

Sondra Miller

Abstract

Hecla Mining Company (HMC) proposed a land transfer with the Idaho Transportation Department (ITD) of their existing North Idaho maintenance facility for a nearby site to be developed into a new maintenance yard. The new site is a former HMC mine tailings impoundment structure (MTIS) and is adjacent to the South Fork of the Coeur d’Alene River and Interstate 90 near Mullan, Idaho. HMC will develop the new site to meet ITD specifications. The engineering tasks necessary to provide ITD with the new maintenance facility on the site include the design of an office building, maintenance shop, truck wash, salt storage shed, and a brine tank containment structure. Roads will be developed to provide all ITD vehicles with access to the various structures and ingress/egress for the nearby interstate. Because soils of the MTIS are contaminated with high levels of lead, arsenic, and other silver mining byproducts, a stormwater system will be designed for the site to effectively prevent water seepage into the MTIS in compliance with the current National Pollutant Discharge Elimination System (NPDES) permit.